This project assesses the effects of drugs of abuse on dominant and submissive behavior in monkeys. It is believed that drugs of abuse may alter these behaviors in humans, and that these alterations may contribute to the system of reinforcers which maintains a drug abuse habit. The project will assess dose response relationships after acute administration and long-term effects during and after chronic administration of barbiturates, amphetamines, narcotics, and alcohol. Choice of drugs for intravenous self-administration by monkeys is also under study.